A mobile telephone has a baseband engine dedicated to implementing the telephony function. In today's mobile phones, the baseband engine (also referred to as “application engine” provides many functions in addition to the conventional telephony application. Additional functions relate to, e.g., user-interface control, rendering of media such as audio and video in the user interface, location-based services, network connectivity and browsing. Small form-factor and autonomy are key issues to mobile phone users. As a result, the base-band engine is a highly integrated system-on-chip (SoC) with a minimum of periphery and with means for implementing a stand-by mode with very-low power consumption. Presently, the base-band engine consumes very low power during times that the cellular front-end is updating with the network for any incoming call. Most of the engine's circuitry is switched off and only little circuitry is powered for sensing a trigger at the RF front-end.
However, the means for implementing the stand-by mode are tailored to the scenario, wherein the mobile phone is waiting for an incoming call and wherein significant data traffic is not required. As soon as the user interacts with the phone (e.g., the user requests interactivity or needs a service), the base-band engine consumes power at a significantly higher level, even while the engine is idling, as its data traffic backbone is designed for high-speed and for concurrent media processing functions. As a result, certain mobile phones equipped with many features cannot be used adequately, because the phone's power pack or battery is being depleted of stored charge within an inconveniently short time period (e.g., a day, or even a couple of hours). This is particularly relevant to the playback of media, such as MP3 data, particularly audio. Users would like to see an increase in playing time. Currently, a playing time of approximately 20 hours is achieved before the battery is to be recharged, and this amount of time is considered too low.
Looking at it from another perspective, a trend has emerged in the field of mobile telephony in the form of newer mobile phones being provided with ever-extending functionality. Various digital technologies are converging on the mobile phone. For example, mobile phones are being equipped with circuitry for applications such as GPS navigation, mobile TV, mobile email, etc. As another example, fixed and mobile telephony are converging in the sense that the modern mobile handsets support both communication via the wide-area cellular access network and communication via a local wireless connection to the Internet (e.g., for voice over IP (VoIP)). The latter trend is being referred to as “fixed-mobile convergence”. The mobile phone platforms resulting from these converging technologies are sometimes referred to as “converging architectures”. Previously, the circuitry implementing the single communication functionality was optimized with regard to, among other things, low power-consumption. Merging various functionalities within the same platform and sharing hardware components among different functionalities renders moot the previous optimizing with respect to low power-consumption.